The present invention relates to free spinning laminated nuts utilizing laminations of hex shaped hardened coned-disc springs, having a central opening tapped to match threads on an associated bolt and a method for making such nuts.
Such laminated nuts have stacked aligned multiple discs retained by a steel outer cage. Examples of prior laminated nut structures are shown and discussed in U.S. Pat. No. 4,383,787, issued to Reynolds on May 17, 1983.
The noted laminated nuts are free running on the bolt until seated. A locking force between the nut and bolt results from the application of additional torque and rotation after initial seating. The additional torque compresses and partially flattens the conical spring discs or spring washers whereby a mechanical interference occurs between the thread flanks of the nut and bolt; it is believed that this is at least partially due to the change in hole size of the nut as the conical discs flatten. The resultant thread interference and retained spring load between thread flanks resists unloading that might otherwise occur as a result of tensile or vibrational loads. Thus, the independently loaded conical spring threaded segments when flattened create a thread interference that tends to lock the nut against rotation or loosening when subject to such loads.
Laminated nuts have been constructed of a hexagonal shape facilitating the application and use of wrenching tools similar to conventional, solid nut constructions. Such previous designs of laminated lock nuts have used symmetrical cages with six fingers or petals, one operative with each of the flats of the laminated, hexagonal configuration. At the same time each of the cage fingers overengaged the exterior surface of the associated flat. With such a construction the wrenching tool engaged the cage fingers and the application and/or removal torque was applied to the laminated nut through the cage. In addition the cage, literally covering the exterior surface of the stacked discs or laminations was somewhat difficult and costly to manufacture and also added to the cost of assembling the discs within the cage.
In the present invention a cage is provided having fewer than six fingers, with each of the fingers being nested in a slot or groove in the surface of the associated flat of the disc. As will be seen this construction provides structural and manufacturing advantages leading to an improved laminated nut.
Therefore it is an object of the present invention to provide a unique laminated nut structure having a cage with fingers located in slots or grooves in the flats of the stacked laminations or discs.
It is another object of the present invention to provide a unique laminated nut structure having fewer fingers than flats on the laminations and with the fingers adapted to be located in slots or grooves in the flats of the stacked laminations.
It is still another object to provide a unique method of manufacturing laminated nuts of the present invention.
It is still another object to provide a unique laminated nut of an improved construction.